ReduceHandler.java

/*
Copyright 2011 Edward Capriolo

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package com.jointhegrid.ironcount.mapreduce;

import com.jointhegrid.ironcount.manager.MessageHandler;
import com.jointhegrid.ironcount.manager.WorkerThread;
import com.jointhegrid.ironcount.manager.Workload;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.HashMap;
import kafka.message.Message;
import kafka.message.MessageAndMetadata;
import me.prettyprint.cassandra.serializers.StringSerializer;
import me.prettyprint.hector.api.Cluster;
import me.prettyprint.hector.api.Keyspace;
import me.prettyprint.hector.api.beans.HCounterColumn;
import me.prettyprint.hector.api.factory.HFactory;
import me.prettyprint.hector.api.mutation.Mutator;

public class ReduceHandler implements MessageHandler {

  HashMap<User,ArrayList<Item>> data = new HashMap<User,ArrayList<Item>>();
  Cluster cluster;
  Keyspace keyspace;
  Workload w;

  public ReduceHandler(){

  }

  @Override
  public void setWorkload(Workload w) {
    this.w = w;
    cluster = HFactory.getOrCreateCluster("mr", w.properties.get("mr.cas"));
    keyspace = HFactory.createKeyspace(w.properties.get("mr.ks"), cluster);
  }

  @Override
  public void handleMessage(MessageAndMetadata<Message> m) {
    String line = getMessage(m.message());
    System.out.println("reduce line "+line);
    String[] parts = line.split("\\|");
    String table = parts[0];
    String row = parts[1];
    String [] columns = row.split(":");

    if (table.equals("user")) {
      User u = new User();
      u.parse(columns);
      if (! data.containsKey(u)){
        data.put(u, new ArrayList<Item>());
      }
    } else if ( table.equals("cart")){
      Item i = new Item();
      i.parse(columns);
      for (User u : data.keySet()){
        if (u.id==i.userfk){
          data.get(u).add(i);
          //counter (items for user)
          incrementItemCounter(u);
          //count ($ spent by user)
          incrementDollarByUser(u,i);
        }
      }
    }
  }


  public void incrementItemCounter(User u){
    try {
      Mutator<String> mut = HFactory.createMutator(keyspace,
              StringSerializer.get());
      HCounterColumn<String> hc = HFactory.createCounterColumn("count", 1L);
      mut.addCounter(u.name, "itemcountbyuser", hc);
      mut.execute();
    } catch (Exception ex) {
      System.out.println(ex);
    }
  }

  public void incrementDollarByUser(User u, Item i){
    try {
      Mutator<String> mut = HFactory.createMutator(keyspace,
              StringSerializer.get());
      HCounterColumn<String> hc = HFactory.createCounterColumn("spent", i.price.intValue());
      mut.addCounter(u.name, "dollarbyuser", hc);
      mut.execute();
    } catch (Exception ex) {
      System.out.println(ex);
    }
  }

  @Override
  public void setWorkerThread(WorkerThread wt) {
    
  }

  public static String getMessage(Message message) {
    ByteBuffer buffer = message.payload();
    byte[] bytes = new byte[buffer.remaining()];
    buffer.get(bytes);
    return new String(bytes);
  }
  @Override
  public void stop() {
  }
}